White matter lesions in patients with localization-related epilepsy

White matter lesions (WML) have been proven to be associated with cognitive impairment. As (1) the decline of cognitive function is the most frequent comorbid disorder in epilepsy, and (2) patients with epilepsy have a relatively high prevalence of WML, the question is raised whether WML in patients with epilepsy are also associated with cognitive decline.

A high-resolution magnetic resonance imaging examination was performed at 3.0 T, comprising T1-weighted, T2 relaxometry, and fluid-attenuated inversion recovery (FLAIR) sequences. Patients with localization-related epilepsy with impaired and unimpaired cognitive functioning and a healthy control group were included. Furthermore, the performance of an automated WML detection algorithm, based on regional intensity evaluation, was assessed.

The prevalence of WML, detected on 3.0 T FLAIR images, is 63% in healthy volunteers and 46% in patients with localization-related, cryptogenic epilepsy. No relationship between WML volume and cognitive performance was observed. The WML volumes from the automated segmentation method were found to be significantly correlated to the volumes obtained by neuroradiologic assessment.

No relations could be found between WML and cognition in the well-defined population of patients with epilepsy. Other clinical characteristics of chronic epilepsy, such as seizures, age of onset, and medication are more likely to play an important role in cognitive decline. Furthermore, the automated WML detection algorithm using a regional Z-score analysis can successfully segment and quantify the WML on FLAIR images.